Method and apparatus for controlling display of content signals

ABSTRACT

A method and apparatus for controlling display of content signals begins by receiving a content signal that includes video content and at least one associated content control indicator. The content signal may also include audio content associated with the video content. The processing continues by comparing the at least one associated content control indicator (e.g., a rating of mature subject matter of the content signal) with at least one content control setting (e.g., a parental setting based on allowable viewing of rated content signals). When the associated content indicator compares unfavorably to the content control setting, a video graphics processor scrambles the at least a portion of the video content. The scrambled video content is then provided to a video rendering device for subsequent display.

RELATED APPLICATIONS

This application is a continuation-in-part of Application Ser. No.09/169,023 filed with the USPTO on Oct. 8, 1998, and has at least oneinventor in common with the prior filed application.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to video and audio processing systemsand more particularly to controlling display of video signals and/oraudio signals.

BACKGROUND OF THE INVENTION

The entertainment industry is producing an ever-increasing number ofvideo and/or audio products for private and public use. Today, aconsumer may rent or purchase a movie in a videocassette format, a laserdisk format, a DVD format, etc. In addition, the user may view a movievia a television broadcast, cable broadcast, and/or satellite broadcast.Similarly, for audio products, a consumer may purchase audiocassettes,CDs, or sound tracks or listen to radio and/or satellite audiobroadcasts. In addition to the numerous sources of audio and/or videomaterials, the content of such merchandise is more explicit than in thepast. As such, the debate over how, and who, should censor such materialis increasing.

The U.S. movie industry has addressed the censorship issue by providingratings to the movies it produces based on the audio and/or videocontent. Such ratings include: G indicating that the content isacceptable for general audiences, PG indicating that parental guidanceis suggested because some of the content may be too mature for allpersons; PG-13 indicating that the movie may be inappropriate forchildren under 13; R indicating that the movie is restricted such thatno one under the age of 17 may view the movie in a theater without hisor her parents; R-17 indicating that no one under the age of 17 isallowed to view the movie in a theater, and X indicating the content isexplicitly for adults. Based on these ratings, parents and/or guardiansmay monitor the movies in which they allow their children to view at amovie theater. While the rating system works fairly well to restrictyounger viewers from viewing inappropriate movies at public theaters, itonly provides guidance to parents and/or guardians for publiclydisplayed movies.

With the increased number of sources for providing audio and/or videocontent into the home, such as cable, satellite, VCR tapes, laser disks,DVD disks, etc., the challenge to monitor a child's viewing choices isbecoming an increasingly difficult task. To address this issue, theUnited States has undertaken a quest to establish a standard that wouldenable a parent to automatically restrict their children's viewing. Sucha standard revolves around parental control technology. In essence,parental control technology allows a parent to enable a video and/oraudio source receiver (e.g., a video cassette player, television, cablebox, satellite receiver, etc.) to restrict the showing of movies thatthe parent has deemed inappropriate. As such, the parent can set aparental control device to any desired level of censoring.

The parental control regulation, as issued by the United States, hasestablished that at least a portion of manufactured video and/or audiosource receivers shall be equipped with the parental control technology,ramping up to full compliance over the next few years. Thus, anymanufacturer that produces a video and/or audio source receiver, whichincludes computers equipped with a video tuner and/or encoder, must becompliant with this standard.

Therefore, a need exists for a method and apparatus that enables acomputer that is capable of presenting video, audio and/or textinformation to be compliant with the parental control standard.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a schematic block diagram of a computing system inaccordance with the present invention;

FIG. 2 illustrates a schematic block diagram of an alternate computingsystem in accordance with the present invention;

FIG. 3 illustrates schematic block diagrams of an audio and videoscrambler in accordance with the present invention;

FIG. 4 illustrates a schematic block diagram of a video graphics enginein accordance with the present invention; and

FIG. 5 illustrates a logic diagram of a method for controlling displayof content signals in accordance with the present invention.

FIG. 6 illustrates a module for a specific audio scramblingimplementation in accordance with the present invention.

FIG. 7 illustrates a block diagram of the use of a polynomialpseudo-scrambler in accordance with the present invention.

FIG. 8 illustrates a schematic block diagram of a mask-type scrambler inaccordance with the present invention.

FIG. 9 illustrates a timing diagram for signals associated with adigital audio signal in accordance with the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Generally, the present invention provides a method and apparatus forcontrolling display of content signals. Such processing begins byreceiving a content signal that includes video, audio, and/or textcontent and at least one associated content control indicator. Note thata separate content control indicator may accompany video, audio, andtext portions of the content signal. The processing continues bycomparing the at least one associated content control indicator (e.g., arating of mature subject matter of the content signal) with at least onecontent control setting (e.g., a parental setting based on allowableviewing of rated content signals). When the associated content indicatorcompares unfavorably to the content control setting, a video graphicsprocessor scrambles the at least a portion of the video content. Thescrambled video content is then provided to a video rendering device forsubsequent display. With such a method and apparatus, a video graphicscontroller and/or personal computer may provide parental controlregarding content signals that include video, audio, and/or textcontent, from being displayed and/or recorded with objectionable maturecontent. By utilizing the content control setting, a user may setindividual settings based on his or her preferences and the level ofcensoring that he or she desires for his or her children.

The present invention can be more fully described with reference toFIGS. 1 through 5. FIG. 1 illustrates a schematic block diagram of acomputing system 10 in accordance with the present invention. Thecomputing system 10 may be a personal computer, a cable box, television,satellite receiver, DVD player, VCR player, video game, etc. Thecomputing system 10 includes a tuner 14, an audio scrambler module 16,an audio decoder 18, an audio processing module 20, a video scramblemodule 22, a video decoder 24, a graphics controller 26, a centralprocessing unit 28, and system memory 30. The computing system 10 isoperably coupled to receive content signals 46 from a video source 12and is further operably coupled to an audio rendering device 32 and avideo rendering device, such as a display 34 and/or a recorder 36. Thevideo source may be a VCR player, DVD player, television broadcast,cable broadcast, satellite broadcast, laser disk player and/or anydevice that sources text content, video content and/or audio content tothe computing system 10.

The content signal includes video, audio, and/or text content and atleast one content control indicator. If the content signal includes asingle content control indicator, the content control indicator appliesto the entire content. For example, if the content control indicator isset to a movie rating of R, the entire content (Video, audio, and/ortext) will be based on this rating. Alternatively, the content signalmay include a plurality of content control indicators associated withvarious segments of video, text, and/or audio content. In this case, thecontent control indicator only regulates the corresponding portion ofthe video, text, and/or audio content. As such, the content signal isselectively controlled and/or censored by the associated content controlindicator.

The tuner 14, which may be a tuner as found in ATI Technologies, Inc.'sAll-in-Wonder board, receives the content signal 46 and separates thevideo content and audio content producing a baseband audio signal 48 anda baseband video signal 50. The audio scramble module 16 receives thebaseband audio signal and scrambles the baseband audio signal asindicated by the scramble control signal 52. Similarly, the videoscramble module 22 receives the baseband video signal 50 and scramblesit based on the scramble control signal.

The graphics controller 26 generates the scramble control signal 52 viaa content controller 40. The content controller 40 includes a processingmodule 42 and memory 44. The processing module 42 may be a singleprocessing entity or a plurality of processing entities. Such aprocessing entity may be a microprocessor, microcontroller,microcomputer, central processing unit, digital signal processor, videographics processor, state machine, logic circuitry, and/or any devicethat manipulates digital information based on programming and/oroperational instructions. The memory 44 may be a single memory device ora plurality of memory devices. Such a memory device may be a read onlymemory device, random access memory, floppy disk, hard drive memory,external memory, magnetic tape memory, DVD memory, CD memory, and/or anydevice that stores operational and/or programming instructions. Notethat if the processing module implements one or more of its functionsvia a state machine or logic circuitry the operational instructionsstored in memory are embedded within the circuitry comprising the statemachine and/or logic circuitry. The operational instructions stored inmemory 44 and executed by processing module 42 will be discussed ingreater detail with reference to FIG. 5.

In general, the content controller 40 receives and/or monitors the videosignal 46, the baseband video signal 50, the decoded video signal 56and/or the video output 60 to detect the content control indicator.Typically, the content controller 40 monitors the baseband video signalfor the content control indicator, however, any other of these signalsmay be used to detect the content control indicator. As one of averageskill in the art would appreciate, if the video output 60 is used tomonitor for the content control indicator, a delay mechanism would needto be employed in the content controller to properly delay theassociated video and/or audio content.

The audio scramble module 16 and the video scramble module 22 areoperable to scramble the respective baseband audio signals 48 and thebaseband video signals 50 when the scramble control signal 52 is active.When the scramble control signal 52 is not active, the audio scramblemodule 16 and video scramble module 22 pass their respective signalsunaltered.

The audio decoder 18 is operably coupled to receive the output from theaudio scramble module 16. The audio decoder 18 produces a decoded audiosignal 54, which is typically in an analog format, and provides it to anaudio processing module 20. The audio decoder 18 may be the type foundin ATI Technology's All-in-Wonder board. The audio processing module 20receives a decoded audio signal, which may be the original audio contentor scrambled audio content, and produces an audio output 58 therefrom.The audio processing module 20 may be a sound card as found incomputers. The output signal 58 is provided to an audio rendering device32, which may be an analog-digital SPDIF, a speaker or plurality ofspeakers, and renders the audio output 58 audible. As such, in the audiopath, if the content controller 40 detects the content control indicatorand determines it exceeds a content control setting, the associatedportion of the audio content will be scrambled thereby providing controlover the level of explicit content that will be rendered audible.

The video decoder 24, which may be of the type found in ATI Technology'sAll-in-Wonder board, receives the output from the video scramble module22 and produces decoded video 56 therefrom. The decoded video isprovided to a video processing engine 38 of the graphics controller 26and may also be received by the central processing unit 28 (e.g., recordthe decoded video). The central processing unit 28 may process thedecoded content signal by storing it in the system memory 30 or inanother memory device associated with the computing system 10. The videoprocessing engine 38 receives the decoded video 56 which may include theoriginal video content or a scrambled representation thereof, andproduces a video output 60. The video output is provided to thevideo-rendering device, which may be a display 34 and/or a recorder 36.As such, the content controller 40, when the content control indicatorassociated with the content signal exceeds the content control setting,controls associated portions of the video content or the entire videocontent by scrambling the baseband video signal 50 or the decoded video56. As such, parental control is provided for video content.

FIG. 2 illustrates a schematic block diagram of an alternate computingsystem 70 in accordance with the present invention. In this embodiment,the computing system 70 includes the audio scramble module 16 coupled tothe output of the audio decoder 18. In addition, the video scramblemodule 22 is coupled to the output of the video decoder 24 or to theoutput of the video processing engine 38. In this embodiment, thedecoded audio signal 54 is typically an analog signal, such that theaudio scramble module 16 operates in the analog domain. Similarly, thevideo scramble module 22 may be acting upon an analog representation ofthe video 60, or, if the display is a digital display, acting upon adigital representation of the video 60. As such, as shown in FIGS. 1 and2, the audio scramble module 16 and the video scramble module 22 may bedigital and/or analog devices. As one of average skill in the art wouldappreciate, the video scramble module 22 may further be incorporated aspart of the graphics controller and/or within the video processingengine 38, which will be discussed with reference to FIG. 4.

The analog path of the computing system 70 further may include an audioattenuation module 72. In general, if the audio signal is scrambled, itmay produce, if unattenuated, an audible signal that would be unpleasantto the user. As such, by including an audio attenuation module 72, whichis activated based on the scramble control signal 52, the scramble audiosignal may have reduced volume.

FIG. 3 illustrates several schematic block diagrams of the audio and/orvideo scramble module 16 and 22. In the first embodiment, the scramblemodule 16 or 22 includes a digital mixer 80 that is operably coupled toreceive the digital audio signal 48, the decoded audio 54, the digitizedcontent signal 50, or the decoded video 56. The scramble module furtherincludes a digital phase shift module 82 operably coupled to alsoreceive the input of the mixing signal. The phase shift module 82 shiftsthe signal (e.g., by 180 degrees+/−90 degrees), which is mixed with theoriginal signal when the scramble control signal 52 is active. As such,when the scramble control signal 52 is active the mixer 80 is mixing theinput signal with a phase shifted representation of the input signalthereby producing a scrambled output.

As an alternate scramble module 16 or 22, the mixer 80 is operablycoupled to receive the corresponding digital input signal and also toreceive a scramble signal via scramble module 84. When the scramblecontrol signal 52 is active, the scramble signal is provided to themixer 80. The scramble signal may be generated as a random numbergenerator, based on the digital input signal, or any other scramblingtechnique that would produce a video output that is unintelligible.

An analog audio scramble module 16 is also shown to include a summingmodule 86 that is operably coupled to receive an audio analog input anda phase shifted representation thereof when the scramble control signal52 is active. As such, by subtracting a phase shifted analogrepresentation of the analog signal from the analog signal the resultingoutput is sufficiently scrambled to render the audio outputsunintelligible.

FIG. 3 further shows an analog audio scramble module 16 that includes amixing node 88, an attenuation module 92 and a scramble signal generator90. When the scramble control signal 52 is active, the scramble signalgenerator 90, which may produce a sinusoidal signal, is mixed with theanalog input by mixer 88. The unintelligible output may then beattenuated via the attenuation module 92. The attenuation module may belinearly controlled by the scramble control signal or function in anoff/on mode as controlled by the scramble control signal 52.

FIG. 6 illustrates a module 505 for a specific [scrambling] audioscrambling implementation in accordance with the present invention. Themodule 505 includes a stereo decoder for receiving an unscrambledrepresentation of an audio signal. The representation can be either ananalog or digital signal that is partitioned into separate analog leftand right audio channels. The left and right analog audio channels areconverted to a digital data stream such as an I2S data stream, throughthe analog-to-digital converter 520, which also performs the necessaryprotocol conversion. The I2S OUT signal is provided to the scrambler530. The digital-to-analog module 530 provides scrambled analog audio tothe multiplexor 540.

When a content signal is de-asserted and applied to the SELECT line, theunscrambled left and right audio channels from the stereo decode 510 areprovided to the LEFT and RIGHT CHANNEL outputs of the module 505 throughmultiplexor 540. In response to an asserted content control signal, thescrambled audio channels from the digital-to-analog converter will beprovided to the LEFT and RIGHT CHANNEL outputs of the module 505. In aspecific implementation of the present invention, the stereo decode 510,the analog-to-digital converter 520, the digital-to-analog converter530, and the multiplexor 540 can be a monolithic devices, such ascommercially available sound chips.

FIG. 7 illustrates the use of a polynomial pseudo scrambler. While manypolynomials may be used, the example of FIG. 7 implements the polynomial1+X4+X7. The digital audio input is provided to a series of delay taps.The polynomial is implemented by providing inputs of selected taps toexclusive-or gates in the manner indicated in FIG. 7. The resultingoutput from the polynomial scrambler is a scrambled representation ofthe digital audio input signal.

FIGS. 8 and 9 illustrates another embodiment of the present inventionfor implementing a mask-type scrambling. FIG. 9 illustrates a timingdiagram for signals associated with a digital audio signal.Specifically, the digital audio includes a clock, channel designation,and data. In FIG. 8, the channel data is received by a mask controlmodule 810. The mask control module 810 provides a masking, or qualifiersignal to the gate 820, whereby the value of the audio output isscrambled by being forced to a predetermined value. The mask control 810may be one-shot device, whereby a masking signal is generated for apredefined period of time in response to a rising or falling edge on thechannel signal. In this embodiment, the gate 820, which receives thedigital data signal and the masking signal, will output a scrambledaudio signal represented in FIG. 9 by the signal labeled SCRAMBLED DATA.The SCRAMBLED DATA signal has portions 901 an 902 of the of the digitalrepresentation forced to a low value. In other embodiments, theSCRAMBLED DATA can be forced high, or forced to specific digital values.In the context herein, the term scrambled data does not necessarilyimply that the scrambled data can be de-scrambled. For example, ascrambling implementation need only to render an audio signal unusable,and not necessarily maintain the ability to reconstruct the signal. Thereason the signal need not be reconstructed is that for parental controlfunctions, it is the final audio out that needs to be unrecognizable.There is no need to reconstruct the final audio out, which is providedto a speaker, amplifier, audio selector, or the like.

FIG. 4 illustrates a schematic block diagram of the video processingengine 38 that may be used for a two dimensional pipeline process and/ora three dimensional pipeline process. The video processing engine 38includes a culling module 102, a Z buffer module 104, a setup module106, a scramble module 100, a rendering module 108, and a frame buffer110. The output of the frame buffer 110 provides the video output 60 toa display driver 112. The culling module 102 is operably coupled toreceive geometric information 114 regarding the content signals to bedisplayed. From this information, the culling module produces Z values116 and culling information 118. The Z values 116 are processed by the Zbuffer module 104 and outputted as Z information 122. The cullinginformation 118 is processed by the setup module 106 to produce setupinformation 120. The rendering module 108 is operably coupled to receivethe Z information 122 and the setup information 120 and producestherefrom rendered images 124. The rendered images are then stored inthe frame buffer 110 and subsequently provided to a display via adisplay driver 112.

The scramble module 100 is operably coupled to the setup module 106and/or the rendering module 108. When coupled to the setup module 106,the scrambling module 100, when activated via the scrambled controlsignal 52, provides the setup module with information that causes it toscramble the setup information 120. For example, the scrambleinformation provided to the setup module 106 may alter the physicalcoordinates of the triangles being rendered and/or the texturecoordinates. In addition, the scramble information may alter the colordata such that when rendered, the images are unintelligible.

When the scramble module 100 is coupled to the rendering module 108, thescramble information provided to the rendering module 108 may cause therendered images 124 to be stored in the frame buffer in a random manner.As such, the scramble information provided to the rendering module maybe random numbers that are added to, subtracted from, or otherwisemathematically used to manipulate the addresses of the frame buffer 110.As such, even though the proper pixel information is being generated, itis scrambled throughout the frame buffer such that the resulting videoimage is unintelligible. As one of average skill in the art wouldappreciate, there are numerous ways in which the scramble module mayalter the function of the video graphics engine to produce a videooutput 60 that is unintelligible.

FIG. 5 illustrates a logic diagram of a method for controlling displayof content signals. The process begins at step 130 where a contentsignal is received, wherein the content signal includes at least oneassociated content control indicator and video content. Note that thecontent signal may further include audio content and/or closed captionedcontent. The process then branches to steps 132 and 142. At step 132,the content control indicator is compared with at least one contentcontrol setting, which is provided by the user of the computing system.For example, if the user is a parent trying to regulate the maturecontent of information that his or her child may view via the computingsystem, the content control setting would reflect the desired maturenature of the subject matter that the parent wishes his or her child toview.

The process then proceeds to step 134 where a determination is made asto whether the comparison is favorable. A favorable comparison is one inwhich the content control indicator is at a rating below the contentcontrol setting. In other words, the content control indicator indicatesthat the corresponding video content, audio content, and/or closecaptioned content is acceptable for unaltered display. If the comparisonwas favorable, the process proceeds to step 136 where the content signalis processed without scrambling.

If, however, the comparison at step 134 was not favorable, the processproceeds to step 138. At step 138, at least a portion of the videocontent is scrambled to produce scrambled video content. In addition, ifthe content signal included audio content it would also be scrambled aswell as any corresponding closed captioned content. In addition toscrambling the audio signal, the scrambled audio signal may beattenuated such that the resulting audible output is minimized. As analternate to scrambling the audio signal, an audio scramble signal maybe provided to an audio processing module such that the audio processingmodule, or audio card, may perform the scramble function. The processthen proceeds to step 140 where the scrambled video content, audiocontent, and/or closed captioned content are provided to the respectivevideo rendering device and/or audio rendering device.

At step 142, the content control indicator is interpreted to determinecopy restriction status. Such copy restriction status includes allowingno copying, allowing single copying, or multiple copies. The processthen proceeds to step 144 where a determination is made as to whetherthe copy restriction is enabled. If not, the process proceeds to step146 where the content signal may be copied. If the copy restriction isenabled, the process proceeds to step 148 where the copying of the videocontent, audio content and/or close captioned content is prevented.

The preceding discussion has presented a method and apparatus forcontrolling display of content signals. By scrambling video content,audio content, and/or close caption content, when a correspondingcontent control indicator compares unfavorably to a user content controlsetting, control of the displaying of objectionable material isobtained. In addition, by utilizing a scrambling technique, the videographics circuitry functions in a similar manner to produce a scrambleoutput and/or the unscrambled output. Thus, minimal additional circuitryis required to achieve parental control.

We claim:
 1. An audio system comprising: an audio decoder with an inputand an output; an analog-to-digital converter having a first inputcoupled to the output of the audio decoder, and an output; a scramblerhaving a first input coupled to the output of the analog-to-digitalconverter, and an output; a digital-to-analog converter having a firstinput coupled to the output of the scrambler and an output; amultiplexor having a first input coupled to the output of the audiodecoder, a second input coupled to the output of the digital-to-analogconverter, and an output; and a multimedia audio output coupled to theoutput of the multiplexor, wherein the multimedia audio output is forproviding an audio signal to an audio playback device.
 2. The audiosystem of claim 1 wherein the audio decoder is a stereo decoder.
 3. Theaudio system of claim 1, wherein the scrambler scrambles an audio signalby using a mask-type scrambler.
 4. The audio system of claim 1, whereinthe scrambler scrambles an audio signal by using a random sequencegenerator.
 5. The audio system of claim 1, wherein the scramblerscrambles an audio signal by using a polynomial pseudo scrambler.
 6. Theaudio system of claim 1, wherein the audio playback device is a speaker.7. The audio system of claim 1, wherein the audio playback device is anamplifier.
 8. The audio system of claim 1, wherein the audio playbackdevice is an audio selector.
 9. The audio system of claim 1, wherein thescrambler is coupled to and operatively responsive to a content controlsignal.
 10. The audio system of claim 9, wherein the multimedia audiooutput corresponds to: the output of the audio decoder when the contentcontrol signal is de-asserted; and the output of the digital-to-analogconverter when the content control signal is asserted.